Google Search can now index Electronic Publication, the .epub, file type. Google added EPUB as a supported filetype to the file types indexable by Google help documentation.
This was added over the past 24-hours, but was likely supported a bit before it was added to the documentation:
This list includes the most common file types Google can index.
Google wrote, "Google Search now supports epub."
I do wonder how well they might rank for normal searches - probably not incredibly well.
Forum discussion at X.
